Turkish President Tayyip Erdogan’s AK Party has submitted its appeal for the annulment and rerun of Istanbul’s municipal elections, broadcaster CNN Turk said on Tuesday, more than two weeks after the vote.

Initial results showed the main opposition Republican People’s Party (CHP) narrowly won control of Turkey’s biggest city in the elections, seemingly ending 25 years of control of a key power center by the AK Party and its Islamist predecessors.

AK Party (AKP) Deputy Chairman Ali Ihsan Yavuz submitted his party’s extraordinary appeal for the annulment and renewal of the elections to Turkey’s High Election Board (YSK) with three suitcases full of documents, CNN Turk said.

If the appeal is approved, renewed elections will take place on the first Sunday 60 days after the initial vote, which will be on June 2. If rejected, the results will be finalized and the winner will receive their mandate to start working.

Repeated AKP challenges have fueled frustration among CHP supporters, which spilled over into football stadiums during the weekend when fans chanted at top Istanbul derby matches for the mayoral mandate to be given to their candidate.

The political uncertainty has added to unease in financial markets. After the latest AK Party comment the lira weakened to 5.8250 against the dollar, it weakest since March 22, bringing its losses this year to 9 percent.

The AK Party has already lost control of the capital Ankara, as well as other key cities across the country. Defeat in Istanbul, where Erdogan was mayor in the 1990s, would be an even greater blow to the president.